A light wave falling on a surface is reflected in more than one plane, namely, horizontal, vertical, or diagonal, resulting in non-polarized light waves. When a viewer views a surface from which non-polarized light wave is being reflected, the non-polarized light wave strikes the viewer's eyes intensely and creates glare. Surface reflections and glare are typically encountered on water and other shiny surfaces. In order to minimize or eliminate glare and hence enable proper viewing by the viewer, the non-polarized light waves are required to be polarized. Polarized light waves are light waves wherein the reflected light waves are in a single plane, namely an operative vertical plane. The process of transforming non-polarized light waves into polarized light waves with the waves oriented in a pre-determined direction is known as polarization. The polarization of light helps reduce glare and enables clear viewing of an image.
There are a variety of methods for polarizing light waves including polarization by transmission, reflection, scattering and refraction of non-polarized light waves. Polarization by refraction is carried out by passing non-polarized light waves from one material to another.
With binoculars different coatings have been applied to lenses to filter the light and reduce glare. These non-glare coatings only filter light and do not actually polarize light.
There have also been a number of attempts to provide binoculars with lenses that polarize light by adding changeable external lenses at the eye piece or objective or by adding a set of polarized glasses. U.S. Pat. No. 2,383,186 describes a polarized lens that pivots about the end of the eye pieces of the binoculars. In contrast, U.S. Pat. No. 3,528,724, U.S. Pat. No. 5,264,916 and U.S. Pat. No. 5,404,225 describes the use of moveable polarized lens in front and away from the array of lens of the binoculars. A different approach was taken in US2007064307 where the coupling of polarized eyeglasses with binoculars was described.
The prior art binoculars suffered problems. The coatings on lens did not provide true polarization of light passing though the lens array. Where the prior art binoculars employed polarized lenses, there were often focus issues.